1. Field of the Invention
The present invention relates to a tape recording system and a head device, both capable of heightening the recording density of a magnetic tape by recording a data signal on adjacent recording tracks.
2. Description of Related Art
Recently, as the amount of information to be dealt with has increased, a recording apparatus has been desired to improve its recording density and its information transfer rate. Accordingly, a magneto-resistive (MR) head having a higher detection sensitivity than that of an inductive head has been adopted, or a multitrack head having a plurality of recording heads arranged therein for recording data signals has been adopted. In particular, in a tape recording system for recording data signals in accordance with a linear recording system, the multitrack head has already been adopted in many formats. As such a tape recording system, for example, a LTO Ultrium (registered trade mark) tape drive is known. LTO Ultrium is a standard for a large capacity high speed tape, which has been drawn up on the basis of a Linear Tape-Open (LTO) technology jointly developed by Hewlett-Packard Inc., IBM Inc. and Seagate Inc. In a magnetic tape type storage system based on such a standard, a plurality of head devices provided on a magnetic head performs recording or reproducing of data simultaneously on a plurality of recording tracks for heightening the transfer rate of data.
Such a head device like a multitrack head is normally used at the time of recording various kinds of data signals on a recording medium in the shape of a tape such as a magnetic tape. As one of the linear recording systems using a multitrack head, a serpentine recording system is known. The serpentine recording system is also adopted in the above-mentioned LTO Ultrium tape drive. The serpentine recording system uses head devices the number of which is less than the number of tracks on a magnetic tape (the sequential switching of relative positions between the tracks and the head devices is required), and performs reading immediately after writing for ensuring reliability at the time of processing data signals. Moreover, the serpentine recording system is a recording system for recording data signals by driving a magnetic tape to perform back-and-forth movement to the multitrack head for achieving the shortening of processing time. The serpentine recording system is adopted by a multi track recording magnetic recording and reproducing apparatus for multitrack storing, represented by a backup storage apparatus for an information processing system and the like. Such a serpentine recording system is disclosed in, for example, Japanese Patent Application Publication H05-046961.
According to Japanese Patent Application Publication H05-046961, as shown in FIG. 6, data signal recording heads W1-W4 and data signal reproducing heads R1-R4 are coupled, respectively, to be arranged in a staggered form. Moreover, data signal recording heads W1-W4 are arranged with a predetermined space between each of them in magnetic gap lines 3c and 3d. The data signal recording heads W1-W4 arranged in such a way enables servo signal recording and reproducing heads being adjacently on the same magnetic gap line to have a substantially double head pitch 2a, and thereby enables the realization of a pattern of recording tracks and data recording heads in which a track pitch, a head pitch and a track width are substantially the same. Such an arrangement of the data recording heads is greatly advantageous for making recording track widths small. For example, when a servo track width is supposed to be 20 μm, the pitch of servo signal recording and reproducing heads being adjacently on the same magnetic gap line is 40 μm. Consequently, even if the sizes of data recording heads are limited, it is possible to provide sufficient spaces between each two of the data recording heads on the magnetic gap line, and thereby the sequential recording of data signals on recording tracks DT1-DT16 is enabled.